body {
    margin: 0;
    background-color: gray;
    overflow: hidden;
    display: flex;
    justify-content: space-between;
    font-family: Arial;
}

.areas {
    position: relative;
    background-color: gray;
    height: 100vh;
    width: calc((100vw - 100vh) / 2);
    box-sizing: border-box;
}

#black_area {
    direction: rtl;
}

.header {
    position: absolute;
    top: 5%;
    margin: 0;
    width: 100%;
    font-size: 6vw;
    text-align: center;
}

#white_header {
    color: white;
    text-shadow: 3px 3px 3px black;
}

#black_header {
    color: black;
    text-shadow: 3px 3px 3px white;
}

.kills_text {
    position: absolute;
    top: 30%;
    margin: 0;
    width: 100%;
    text-align: center;
    font-size: 3vw;
    color: yellow;
    text-shadow: 3px 3px 3px black;
}

.kills_container {
    position: absolute;
    top: 100%;
    transform: translateY(-100%);
    width: 100%;
    aspect-ratio: 1 / 1;
    border-top: 0.5vh solid black;
}

.kills_images {
    height: 25%;
    aspect-ratio: 1 / 1;
}

#board {
    line-height: 0;
    height: 100vh;
    aspect-ratio: 1 / 1;
}

.btns {
    width: 12.5%; /* 1/8 of the board */
    height: 12.5%; /* 1/8 of the board */
    background-size: cover;
    vertical-align: top;
    border: none;
    cursor: pointer;
    transition: opacity 0.1s;
}

.btns:hover {
    opacity: 0.8;
}

.turn_area {
    animation: turnMark 1s alternate infinite ease-out;
}

@keyframes turnMark {
    0% {
        box-shadow: inset 0 0 20px rgba(0,0,255,0.5);
        background-color: rgb(150, 150, 150);
    }
    100% {
        box-shadow: inset 0 0 65px rgba(0,0,255,0.5);
        background-color: rgb(140, 140, 140);
    }
}